Shear behavior of hydrophilic and hydrophobic unsaturated sands

CHEN Yulong; SUN Huan

doi:10.16511/j.cnki.qhdxxb.2019.22.027

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Journal of Tsinghua University(Science and Technology) ›› 2019, Vol. 59 ›› Issue (12) : 961-966. DOI: 10.16511/j.cnki.qhdxxb.2019.22.027

HYDRAULIC ENGINEERING

Shear behavior of hydrophilic and hydrophobic unsaturated sands

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Abstract

Meniscus water affects the shear strength of unsaturated soils. The soil wettability affects the physio-mechanical behavior, the contact angle and the capillary pressure. The current geotechnical knowledge of these effects in unsaturated soils is mostly limited to hydrophilic soils. This paper analyzed hydrophobic and hydrophilic sands to show how meniscus water affects the shear behavior of unsaturated soils using artificially synthesized hydrophobic sands. In addition, the measured shear strengths were analyzed based on the suction stress. The results show that the meniscus water greatly influences the unsaturated shear behavior. The shear strength and dilatancy of hydrophilic sands are greater than those of hydrophobic sands. For hydrophobic sands, the water in the soil is not in the form of meniscus water, but in the form of water droplets on the particle surface. Therefore, the initial saturation has little effect on the shear strength, but a large effect on the dilatancy. For hydrophilic sands, the shear strength increases with decreasing initial saturation.

Key words

meniscus water / hydrophilic sand / hydrophobic sand / unsaturated soil / suction

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CHEN Yulong, SUN Huan. Shear behavior of hydrophilic and hydrophobic unsaturated sands[J]. Journal of Tsinghua University(Science and Technology). 2019, 59(12): 961-966 https://doi.org/10.16511/j.cnki.qhdxxb.2019.22.027

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